This invention is directed to a shock sensor mounted in an electronic device.
Some electronic devices are provided with shock sensors to determine the level of shock events to which the electronic device is subjected over the course of its lifetime. In some cases, the shock sensors may be used for warranty purposes (e.g., the warranty is invalid if the electronic device is subjected to a shock event that exceeded the shock event of a 10 foot drop). Shock sensors can be classified in two categories: active shock sensors and passive shock sensors.
Active shock sensors can include an accelerometer configured to generate a signal when the accelerometer detects a level of acceleration that corresponds to an impact threshold level. The signal may then be read by detection circuitry without disassembling the electronic device.
An inherent limitation of some active shock sensors, such as those that include accelerometers, is that they require power to operate. This means that they consume power while the device operates, and will not function if the device fails (e.g., the device does not power up). In addition, adding an active shock sensor may require circuit board modifications. Furthermore, if the electronic device is severely damaged, the active sensor may be rendered inoperable or diagnostic equipment may not be able to obtain data from the sensor or storage medium containing shock sensing information. Finally, active shock sensors are relatively expensive, at least compared to various passive sensors.
Passive shock sensors typically include an ink capsule that is enclosed in a tube. The capsule is constructed such that it breaks when the electronic device is subjected to a shock event that exceeds an impact threshold level. When the capsule ruptures, the ink (or other colored liquid contained in the capsule) is released and fills the tube. A technician may then disassemble the electronic device and observe the shock sensor to determine, based on the location the ink in the shock sensor, whether the electronic device was subjected to a shock event that exceeded the impact threshold level.
While passive shock sensors do not exhibit some of the limitations of active shock sensors, they are generally not resettable. This requires the shock sensor to be replaced when the electronic device is repaired or refurbished. In addition, there is typically no method for observing the shock sensor from the outside of the electronic device. Instead, the technician must disassemble the device to access the shock sensor.
Accordingly, it would be desirable to provide a shock sensor that exhibits both active and passive attributes. In particular, it would be desirable to provide a shock sensor that can be analyzed without disassembling the device. It would also be desirable to provide a shock sensor that can be analyzed when the device has failed and electronic detection is not possible.